Patents by Inventor Sai-Kwing Lau
Sai-Kwing Lau has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Patent number: 7378362Abstract: The present invention is a composite material, a process and a product formed by the process. The composite is formed by a process that includes forming a fibrous structure comprising fibers into a preform, coating the fibers of the fibrous structure preform with elemental carbon to impregnate that preform, infiltrating the preform with boron carbide to form an impregnated green body. The impregnated green body is infiltrated with liquid naphthalene or other carbon precursor, which is thereafter pyrolyzed to form a carbon char. Then, the char infiltrated green body is infiltrated with molten silicon to form a continuous matrix throughout the composite. The silicon in the continuous matrix is reacted with the carbon char to form silicon carbide.Type: GrantFiled: October 24, 2003Date of Patent: May 27, 2008Assignee: Goodrich CorporationInventors: Thomas Dwayne Nixon, Sai-Kwing Lau, Edward R. Stover, Salvatore J. Calandra, Vijay V. Pujar, Lanny Ritz, Gary L. Clark, Steve T. Keller
-
Patent number: 6855428Abstract: The present invention is a composite material and process to produce same. That material comprises a fibrous structure which is initially predominantly coated with elemental carbon; that fibrous structure is then subsequently predominantly coated with at least one ceramic material, e.g., boron carbide, which is non-reactive with silicon. The composite material also comprises a silicon matrix which is continuous and predominantly surrounds the fibrous structure, which has been initially predominantly coated with elemental carbon and subsequently predominantly coated with at least one ceramic material. The matrix which has a fine grain crystalline structure of predominantly 20 microns or less in size. The at least one ceramic material is discontinuous within that matrix. The fibrous material pulls out of the elemental carbon, which initially predominantly coats that fibrous structure, when the composite is subjected to fracture.Type: GrantFiled: June 2, 2003Date of Patent: February 15, 2005Assignee: B. F. Goodrich CompanyInventors: Sai-Kwing Lau, Salvatore J. Calandra, Thomas D. Nixon, Edward R. Stover
-
Publication number: 20040192534Abstract: The present invention is a composite material, a process and a product formed by the process. The composite is formed by a process that includes forming a fibrous structure comprising fibers into a preform, coating the fibers of the fibrous structure preform with elemental carbon to impregnate that preform, infiltrating the preform with boron carbide to form an impregnated green body. The impregnated green body is infiltrated with liquid naphthalene or other carbon precursor, which is thereafter pyrolyzed to form a carbon char. Then, the char infiltrated green body is infiltrated with molten silicon to form a continuous matrix throughout the composite. The silicon in the continuous matrix is reacted with the carbon char to form silicon carbide.Type: ApplicationFiled: October 24, 2003Publication date: September 30, 2004Inventors: Thomas Dwayne Nixon, Sai-Kwing Lau, Edward R. Stover, Salvatore J. Calandra, Vijay V. Pujar, Lanny Ritz, Gary L. Clark, Steve T. Keller
-
Publication number: 20040058154Abstract: The present invention is a composite material and process to produce same. That material comprises a fibrous structure which is initially predominantly coated with elemental carbon; that fibrous structure is then subsequently predominantly coated with at least one ceramic material, e.g., boron carbide, which is non-reactive with silicon. The composite material also comprises a silicon matrix which is continuous and predominantly surrounds the fibrous structure, which has been initially predominantly coated with elemental carbon and subsequently predominantly coated with at least one ceramic material. The matrix which has a fine grain crystalline structure of predominantly 20 microns or less in size. The at least one ceramic material is discontinuous within that matrix. The fibrous material pulls out of the elemental carbon, which initially predominantly coats that fibrous structure, when the composite is subjected to fracture.Type: ApplicationFiled: June 2, 2003Publication date: March 25, 2004Inventors: Sai-Kwing Lau, Salvatore J. Calandra, Thomas D. Nixon, Edward R. Stover
-
Patent number: 6245424Abstract: This invention relates to a process comprising the steps of: a) providing a fiber preform comprising a non-oxide ceramic fiber with at least one coating, the coating comprising a coating element selected from the group consisting of carbon, nitrogen, aluminum and titanium, and the fiber having a degradation temperature of between 1400° C. and 1450° C., b) impregnating the preform with a slurry comprising silicon carbide particles and between 0.1 wt % and 3 wt % added carbon c) providing a cover mix comprising: i) an alloy comprising a metallic infiltrant and the coating element, and ii) a resin, d) placing the cover mix on at least a portion of the surface of the porous silicon carbide body, e) heating the cover mix to a temperature between 1410° C. and 1450° C. to melt the alloy, and f) infiltrating the fiber preform with the melted alloy for a time period of between 15 minutes and 240 minutes, to produce a ceramic fiber reinforced ceramic composite.Type: GrantFiled: July 10, 1998Date of Patent: June 12, 2001Assignee: Saint-Gobain Industrial Ceramics, Inc.Inventors: Sai-Kwing Lau, Salvatore J. Calandra, Roger W. Ohnsorg
-
Patent number: 5945062Abstract: The invention includes a process for producing a reaction bonded silicon carbide composite reinforced with coated silicon carbide fibers which is suitable for high temperature applications. The process includes the steps of coating SiC fibers with AlN, BN or TiB.sub.2 ; treating the coated fibers with a mixture of SiC powder, water and a surfactant; preparing a slurry comprising SiC powder and water; infiltrating the coated fibers with the slurry to form a cast; drying the cast to form a green body; and reaction bonding the green body to form a dense SiC fiber reinforced reaction bonded matrix composite.The invention further includes a SiC fiber reinforced SiC composite comprising a reaction bonded SiC matrix, a SiC fiber reinforcement possessing thermal stability at high temperatures and an interface coating on the fibers having chemical and mechanical compatibility with the SiC matrix and with the SiC fibers.Type: GrantFiled: February 17, 1998Date of Patent: August 31, 1999Assignee: The Carborundum CompanyInventors: Stephen Chwastiak, Sai-Kwing Lau, Carl H. McMurtry, Gajawalli V. Srinivasan
-
Patent number: 5840221Abstract: A process comprising the steps of:a) providing a fiber preform comprising a non-oxide ceramic fiber with at least one coating, the coating comprising a coating element selected from the group consisting of carbon, nitrogen, aluminum and titanium, and the fiber having a degradation temperature of between 1400.degree. C. and 1450.degree. C.,b) impregnating the preform with a slurry comprising silicon carbide particles and between 0.1 wt % and 3 wt % added carbonc) providing a cover mix comprising:i) an alloy comprising a metallic infiltrant and the coating element, andii) a resin,d) placing the cover mix on at least a portion of the surface of the porous silicon carbide body,e) heating the cover mix to a temperature between 1410.degree. C. and 1450.degree. C. to melt the alloy, andf) infiltrating the fiber preform with the melted alloy for a time period of between 15 minutes and 240 minutes, to produce a ceramic fiber reinforced ceramic composite.Type: GrantFiled: December 2, 1996Date of Patent: November 24, 1998Assignee: Saint-Gobain/Norton Industrial Ceramics CorporationInventors: Sai-Kwing Lau, Salavatore J. Calandra, Roger W. Ohnsorg
-
Patent number: 5834387Abstract: Silicon carbide sintered bodies having controlled porosity in the range of about 2 to 12 vol %, in which the pores are generally spherical and about 50 to 500 microns in diameter, are prepared from raw batches containing a polymer fugitive. Sintered bodies in the form of mechanical seal members exhibit lower power consumption at low PV and, in addition, lower wear rates at high PV in comparison to commercially available silicon carbide seal members.Type: GrantFiled: July 25, 1997Date of Patent: November 10, 1998Assignee: The Carborundum CompanyInventors: Ramesh Divakar, Sai-Kwing Lau
-
Patent number: 5817432Abstract: The invention includes a process for producing a reaction bonded silicon carbide composite reinforced with coated silicon carbide fibers which is suitable for high temperature applications. The process includes the steps of coating SiC fibers with AlN, BN or TiB.sub.2 ; treating the coated fibers with a mixture of SiC powder, water and a surfactant; preparing a slurry comprising SiC powder and water; infiltrating the coated fibers with the slurry to form a cast; drying the cast to form a green body; and reaction bonding the green body to form a dense SiC fiber reinforced reaction bonded matrix composite.The invention further includes a SiC fiber reinforced SiC composite comprising a reaction bonded SiC matrix, a SiC fiber reinforcement possessing thermal stability at high temperatures and an interface coating on the fibers having chemical and mechanical compatibility with the SiC matrix and with the SiC fibers.Type: GrantFiled: August 16, 1996Date of Patent: October 6, 1998Assignee: The Carborundum CompanyInventors: Stephen Chwastiak, Sai-Kwing Lau, Carl H. McMurtry, Gajawalli V. Srinivasan
-
Patent number: 5643514Abstract: The invention includes a process for producing a reaction bonded silicon carbide composite reinforced with coated silicon carbide fibers which is suitable for high temperature applications. The process includes the steps of coating SiC fibers with AlN, BN or TiB.sub.2 ; treating the coated fibers with a mixture of SiC powder, water and a surfactant; preparing a slurry comprising SiC powder and water; infiltrating the coated fibers with the slurry to form a cast; drying the cast to form a green body; and reaction bonding the green body to form a dense SiC fiber reinforced reaction bonded matrix composite.The invention further includes a SiC fiber reinforced SiC composite comprising a reaction bonded SiC matrix, a SiC fiber reinforcement possessing thermal stability at high temperatures and an interface coating on the fibers having chemical and mechanical compatibility with the SiC matrix and with the SiC fibers.Type: GrantFiled: May 22, 1995Date of Patent: July 1, 1997Assignee: The Carborundum CompanyInventors: Stephen Chwastiak, Sai-Kwing Lau, Carl H. McMurtry, Gajawalli V. Srinivasan
-
Patent number: 5635430Abstract: Silicon carbide sintered bodies having controlled porosity in the range of about 2 to 12 vol %. in which the pores are generally spherical and about 50 to 500 microns in diameter, are prepared from raw batches containing a polymer fugitive. Sintered bodies in the form of mechanical seal members exhibit lower power consumption at low PV and, in addition, lower wear rates at high PV in comparison to commercially available silicon carbide seal members.Type: GrantFiled: June 1, 1995Date of Patent: June 3, 1997Assignee: The Carborundum CompanyInventors: Ramesh Divakar, Sai-Kwing Lau, Stephen Chwastiak
-
Patent number: 5589428Abstract: Silicon carbide sintered bodies having controlled porosity in the range of about 2 to 12 vol %. in which the pores are generally spherical and about 50 to 500 microns in diameter, are prepared from raw batches containing a polymer fugitive. Sintered bodies in the form of mechanical seal members exhibit lower power consumption at low PV and, in addition, lower wear rates at high PV in comparison to commercially available silicon carbide seal members.Type: GrantFiled: June 5, 1995Date of Patent: December 31, 1996Assignee: The Carborundum CompanyInventors: Ramesh Divakar, Sai-Kwing Lau
-
Patent number: 5484655Abstract: The invention provides a silicon carbide fiber carrying an aluminum nitride coating between about 1 and about 15 micrometers thick. The AlN coating serves as a debond layer which improves the fracture toughness of composite materials in which the coated fiber is a reinforcement phase.Type: GrantFiled: November 4, 1993Date of Patent: January 16, 1996Assignee: The Carborundum CompanyInventors: Sai-Kwing Lau, Carl H. McMurtry
-
Patent number: 5436042Abstract: This invention is directed to substantially strain-free, shaped, sintered ceramic fabric preform segments, to the production of the sintered preform segments from novel fixtured, shaped, green ceramic fabric preforms, and to sintered ceramic fiber-reinforced composite articles prepared from the sintered preforms and characterized in that the reinforcement phase is substantially free of mechanical strain, and the fiber in the fabric can exhibit a very small bending radius.Type: GrantFiled: March 11, 1994Date of Patent: July 25, 1995Assignee: The Carborundum CompanyInventors: Sai-Kwing Lau, Roger W. Ohnsorg, Salvatore J. Calandra
-
Patent number: 5395807Abstract: Silicon carbide sintered bodies having controlled porosity in the range of about 2 to 12 vol %. in which the pores are generally spherical and about 50 to 500 microns in diameter, are prepared from raw batches containing a polymer fugitive. Sintered bodies in the form of mechanical seal members exhibit lower power consumption at low PV and, in addition, lower wear rates at high PV in comparison to commercially available silicon carbide seal members.Type: GrantFiled: May 25, 1993Date of Patent: March 7, 1995Assignee: The Carborundum CompanyInventors: Ramesh Divakar, Sai-Kwing Lau
-
Patent number: 5202105Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.Type: GrantFiled: July 5, 1990Date of Patent: April 13, 1993Assignee: Stemcor CorporationInventors: Wolfgang D. G. Boecker, Stephen Chwastiak, Tadeusz M. Korzekwa, Sai-Kwing Lau
-
Patent number: 5002905Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.Type: GrantFiled: April 22, 1988Date of Patent: March 26, 1991Assignee: Stemcor CorporationInventors: Wolfgang D. G. Boecker, Stephen Chwastiak, Tadeusz M. Korzekwa, Sai-Kwing Lau
-
Patent number: 4981665Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.Type: GrantFiled: April 22, 1988Date of Patent: January 1, 1991Assignee: Stemcor CorporationInventors: Wolfgang D. G. Boecker, Stephen Chwastiak, Tadeusz M. Korzekwa, Sai-Kwing Lau
-
Patent number: 4756895Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.Type: GrantFiled: August 22, 1986Date of Patent: July 12, 1988Assignee: Stemcor CorporationInventors: Wolfgang D. G. Boecker, Stephen Chwastiak, Tadeusz M. Korzekwa, Sai-Kwing Lau
-
Patent number: 4479868Abstract: The invention provides both preferred material alloys and electrode lead wire configurations for electrically connecting the solid electrolyte cell in a gas sensing probe to a remote measuring circuit.Type: GrantFiled: October 21, 1983Date of Patent: October 30, 1984Assignee: Westinghouse Electric Corp.Inventors: William H. McIntyre, Sai-Kwing Lau, Subhash C. Singhal